Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Volume 51, Issue 1
Displaying 1-12 of 12 articles from this issue
Review
  • Katsuyuki Murata, Toyoto Iwata, Miwako Dakeishi, Kanae Karita
    Article type: Review
    2009 Volume 51 Issue 1 Pages 1-12
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: November 06, 2008
    JOURNAL FREE ACCESS
    Objectives: The Scientific Committee on Neurotoxicology and Psychophysiology and the Scientific Committee on the Toxicology of Metals of the International Commission on Occupational Health in 2006 recommended that the standard for blood lead (BPb) levels be reduced to 30 μg/dl for industrial workers and 5 μg/dl for children. To examine whether the critical level of lead producing adverse effects truly differs between workers and children, we provided an overview of studies addressing the critical level of lead in workers, together with a perspective on lead toxicity in children. Data sources and extraction: In 25 reports published in English with keywords of "benchmark dose (BMD)," "lead" and "humans," only five studies proved to be relevant to lead toxicity. Four more studies with figures illustrating significant relationships between lead and neurotoxic outcomes were selected. Data synthesis: Based on data from previous reports using a BMD approach, the critical organ of lead in workers was thought to be the nervous system and the critical BPb level (number-weighted mean) was between 10.7 and 17.5 μg/dl. The neurotoxic effects of lead exposure at such levels seemed reversible. The BPb level at which lead-associated intellectual deficits occurred in children was as low as the critical level of BPb (below 5 μg/dl) for inhibited heme synthesis in workers. Conclusions: The neurotoxic effects of lead in workers appear to be initiated at BPb levels below 18 μg/dl, which are somewhat higher than the critical level of lead neurotoxicity in children. Each national institute for risk management should take evidence-based preventive action against subclinical lead poisoning in workers, as well as in children.
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  • Jessica de Bloom, Michiel Kompier, Sabine Geurts, Carolina de Weerth, ...
    Article type: Review
    2009 Volume 51 Issue 1 Pages 13-25
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 19, 2008
    JOURNAL FREE ACCESS
    Objectives: The aim of this meta-analysis is to investigate to what extent vacation has positive effects on health and well-being, how long such effects endure after work resumption, and how specific vacation activities and experiences affect these relationships. Methods: Based on a systematic literature search (PsycInfo, Medline) and methodological exclusion criteria, in a stepwise approach, 7 studies were selected and reviewed. Effect sizes (Cohen's d) were calculated i) for every outcome variable within every study, ii) for every study by averaging the effect sizes per study, and iii) for homogeneous categories of outcome variables (exhaustion, health complaints, life satisfaction). Results: The results suggest that vacation has positive effects on health and well-being (small effect, d=+0.43), but that these effects soon fade out after work resumption (small effect, d=-0.38). Our research further demonstrated that vacation activities and experiences have hardly been studied. Therefore, their contribution to vacation effect and fade out remains unclear. Discussion: Progress in future vacation research will depend on strong research designs that incorporate repeated measurements pre-, inter- and post-vacation.
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Original
  • Tomoko Ikeda, Akinori Nakata, Masaya Takahashi, Minoru Hojou, Takashi ...
    Article type: Original
    2009 Volume 51 Issue 1 Pages 26-37
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 05, 2008
    JOURNAL FREE ACCESS
    Background: Although the relationship between job stress and depressive symptoms has been well documented among workers in large scale enterprises, the situation in small- and medium-scale enterprises (SMEs) is not fully understood. Objectives: To clarify the factors associated with depressive symptoms in SMEs in Japan. Methods: 1,516 male and 738 female Japanese workers at SMEs were surveyed using a self-administered questionnaire. We applied hierarchical multiple linear regression with depressive symptoms (Center for Epidemiologic Studies Depressive Symptoms Scale) as the dependent variable, and (1) Individual, (2) Lifestyle, (3) Job stressors, and (4) SME unique factors as independent variables entered in 4 steps. Analyses were stratified by sex due to large differences in stress scores and demographic variables. Results: Perceived lack of understanding from others with regard to health was the strongest factor associated with increased depressive symptoms (BETA=0.29 in males and 0.28 in females). Higher intragroup conflict (BETA=0.15 in males and 0.09 in females), perceived job future ambiguity (BETA=0.09 in males and 0.11 in females), higher quantitative workload (BETA=0.06 in males and 0.10 in females), and being an employer or a member of the employer's family (BETA=0.06 in males and 0.10 in females) were additional factors associated with high depressive symptoms. Economic concern, being single, cigarette smoking, shorter sleep duration, and skill underutilization were male specific, while younger age and lower social support at work were female specific factors significantly associated with increased depressive symptoms. Conclusions: These data suggest that poor mental health may be prevented by creating a workplace climate which focuses on the high value of the health of fellow workers.
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  • Satoko Iwasawa, Yuriko Kikuchi, Yuji Nishiwaki, Makiko Nakano, Takehir ...
    Article type: Original
    2009 Volume 51 Issue 1 Pages 38-47
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: November 06, 2008
    JOURNAL FREE ACCESS
    Background: Mt. Oyama in Miyakejima Island erupted in June, 2000. All Miyake villagers were forced to evacuate from the island in September, 2000, due to continuous eruptions and emissions of unsafe amounts of volcanic gas, mainly SO2. From February, 2005, Miyake villagers returned to the island despite volcanic gas still being emitted. Objectives: This study examines the 2-yr changes in Miyake residents' respiratory systems from autumn 2004 to November 2006. Methods: The study population was 823 Miyake adult residents who participated in the health check-up in 2006. Respiratory effects were evaluated by a questionnaire for respiratory symptoms and spirometry. SO2 has been continuously monitored at 7 sampling points of the inhabited area. The mean SO2 concentration from February 2005 to November 2006 was 0.031 ppm. The area was categorized into 4 areas by SO2 concentration, namely, areas L, H-1, H-2 and H-3, where average SO2 concentrations were 0.019, 0.026, 0.032, and 0.045 ppm, respectively. Results: The study subjects showed no deterioration in lung function. Prevalence of cough and phlegm among all participants were significantly higher in 2006 than in 2004, and age-, sex- and smoking-adjusted odds ratios of cough and phlegm were 1.75 (95%CI 1.33-2.30) and 1.44 (1.12-1.87). Prevalence of chronic bronchitis-like symptoms among normosusceptive subjects in 2006 was 4.1% which was significantly higher than that of 2.1% in 2004 (p=0.035). Compared to area L, the frequencies of phlegm and irritation of the nose were significantly increased in areas H-2 and H-3. Conclusion: SO2 exposure-related respiratory symptoms were observed in adult Miyakejima residents after returning to the island.
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  • Chihiro Nishiura, Rie Narai, Takayuki Ohguri, Atsushi Funahashi, Keiic ...
    Article type: Original
    2009 Volume 51 Issue 1 Pages 48-56
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 05, 2008
    JOURNAL FREE ACCESS
    Objectives: To identify the effect of worksite smoking prevalence on individual cessation behavior. Methods: We conducted a cohort study at a Japanese worksite without a total ban on smoking, but with designated smoking areas. Baseline data were obtained in 2005 through a self-administered questionnaire from 15,229 workers in 322 work units as part of annual health checkups, and followed up in 2006. Data on smoking status, time to first cigarette after waking up, desire to quit, number of cigarettes smoked per day, and respiratory symptoms were obtained. Details like workers' demographics, blue/white-collar workers, night shift duties, administrative position, and work unit codes were obtained from the firm's administrative records. Smoking prevalence in work units was calculated as a ratio, standardized by age, and categorized into quartiles. Multiple logistic regression was used to predict cessation by smoking prevalence, adjusting for individual level variables. Results: In the lowest smoking prevalence quartile compared with the highest, odds ratios (95% CI) of cessation among those who smoked their first cigarette more than 30 min after waking up were 2.32 (1.06, 5.09) in white-collar units and 1.86 (0.98, 3.55) in blue-collar units, and that among those with a moderate desire to quit was 2.05 (0.94, 4.49) in white-collar units. Conclusion: Worksite smoking prevalence affects the likelihood of successful cessation, especially among those with less nicotine dependence and who are in the early stage of behavioral change. This suggests that serious consideration should be placed not only on individual behavior modification but also on modification of worksite conditions.
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  • Xing Liu, De-Ying Zhang, Ya-Sha Li, Jing Xiong, Da-Wei He, Tao Lin, Xu ...
    Article type: Original
    2009 Volume 51 Issue 1 Pages 57-63
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 19, 2008
    JOURNAL FREE ACCESS
    Objectives: To investigate the effect of di-(2-ethylhexyl) phthalate (DEHP) on the expression of activating transcription factor 3 (ATF3) and apoptosis of fetal mouse genital tubercle (GT). Methods: In this developmental toxicity study, pregnant C57BL/6 mice were exposed to corn oil or DEHP (100 or 500 mg/kg/day) from embryonic day 12 (ED12) to ED16. Apoptosis was characterized by Terminal transferase dUTP nick end labeling (TUNEL) assay. Using RT-PCR and western blot, the expressions of ATF3 and apoptosis-related genes (P53, Bcl-2 and Bax) were investigated. Results: Apoptosis of fetal mouse GT cells notably decreased after DEHP treatment. DEHP activated ATF3 both at the mRNA and protein levels in GT. Furthermore, pro-apoptotic P53 was downregulated and the ratio of anti-apoptotic (Bcl-2)/pro-apoptotic (Bax) was not significantly changed. Conclusions: These results suggest that DEHP may induce external genital defects via a mechanism involving apoptosis, which might correlate with the regulation of ATF3 and P53 expressions.
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  • Rustam Sadykov, Ilya Digel, Aysegül Temiz Artmann, Dariusz Porst, ...
    Article type: Original
    2009 Volume 51 Issue 1 Pages 64-73
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 19, 2008
    JOURNAL FREE ACCESS
    Objectives: Lead's (Pb(II)) possible role in intestinal pathologies of microbial etiology remains mostly unknown. The aim of this study was to examine the effects of lead on the gut microbial community and its interactions with rat intestinal epithelium. Methods: The lead-induced changes in different intestinal microbial groups (lactose-positive lac(+) and -negative lac(-) E.coli strains, lactobacilli and yeasts) were followed separately by the colony-forming unit (CFU) method. Samples were taken from outbred white rats subjected to different exposure schedules. Additionally, the impact of different lead doses on microbial adhesion to cultured intestinal cells (IEC-6) was investigated. Finally, the lead accumulation and distribution were measured by means of atomic absorption spectrometry. Results: For the first time it was shown that oral lead exposure causes drastic changes in the gut microbial community. Proportional to the lead dose received, the relative number of lactose-negative E.coli cells increased dramatically (up to 1,000-fold) in comparison to the other microbial groups during 2 wk of exposure. Considering the number of microbes in the intestine, such a shift in intestinal microflora (dysbacteriosis) is very significant. Adhesion studies showed certain stimulating effects of lead on E. coli attachment to rat intestinal epithelium as compared to Lactobacillus attachment. Conclusions: The mechanisms providing the apparent competitive success of the lac(-) group are unclear but could be related to changes in surface interactions between microbial and host cells. This study may provide important clues for understanding the pathological effects of metal dietary toxins in human beings.
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  • Akiomi Inoue, Norito Kawakami, Akizumi Tsutsumi, Akihito Shimazu, Masa ...
    Article type: Original
    2009 Volume 51 Issue 1 Pages 74-83
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 19, 2008
    JOURNAL FREE ACCESS
    Objectives: Previous European studies reporting low procedural justice and low interactional justice were associated with increased health problems have used a modified version of the Moorman's Organizational Justice Questionnaire (OJQ, Elovainio et al., 2002) to assess organizational justice. We translated the modified OJQ into the Japanese language and examined the internal consistency reliability, and factor-based and construct validity of this measure. A back-translation procedure confirmed that the translation was appropriate, pending a minor revision. Methods: A total of 185 men and 58 women at a manufacturing factory in Japan were surveyed using a mailed questionnaire including the OJQ and other job stressors. Results: Cronbach alpha coefficients of the two OJQ subscales were high (0.85-0.94) for both sexes. The hypothesized two factors (i.e., procedural justice and interactional justice) were extracted by the factor analysis for men; for women, procedural justice was further split into two separate dimensions supporting a three- rather than two-factor structure. Convergent validity was supported by expected correlations of the OJQ with job control, supervisor support, effort-reward imbalance, and job future ambiguity in particular among the men. Conclusion: The present study shows that the Japanese version of the OJQ has acceptable levels of reliability and validity at least for male employees.
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Field Study
  • Hiroko Fujii, Takashi Muto
    Article type: Field Study
    2009 Volume 51 Issue 1 Pages 84-90
    Published: 2009
    Released on J-STAGE: February 11, 2009
    Advance online publication: December 19, 2008
    JOURNAL FREE ACCESS
    Objectives: This study investigated the characteristics of health education programs and the health behavior theories used to establish more effective programs for Japanese companies. Methods: The study surveyed 1,372 companies with 500 or more employees. In a cross-sectional study, the characteristics of the health education programs were surveyed using a questionnaire, which included items regarding target lifestyle-related diseases and lifestyle areas, and the health behavior theories used to develop the present status and future plans. Results: One hundred ninety companies responded giving a response rate of 13.8%. At the time of the survey, the most common diseases targeted for primary prevention were obesity (27.1%), hypertension (22.7%), hyperlipidemia (22.1%), and diabetes (22.1%). Approximately 60% of the respondents were implementing health education programs that targeted certain lifestyles, and the most frequently reported target lifestyles were diet (41.0%) and exercise (38.2%). At the time of the survey, 40% of respondents had implemented programs that included health behavior theory, and 55.6% were going to implement such program plans in the future, a significantly higher percentage than at the time of the survey. Conclusions: In Japanese workplaces, it has been suggested that programs that include health behavior theories have not been implemented frequently enough, but such programs are expected to become more common in the future. The findings of this survey may be useful for planning health education programs using health behavior theories to establish more effective programs for Japanese companies.
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Case Study
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